Using Uniaxial Stress to Probe the Relationship between Competing Superconducting States in a Cuprate with Spin-stripe Order

Abstract

We report muon spin rotation and magnetic susceptibility experiments on in-plane stress effects on the static spin-stripe order and superconductivity in the cuprate system La 2−x Ba x CuO 4 with x ¼ 0.115. An extremely low uniaxial stress of ∼0.1 GPa induces a substantial decrease in the magnetic volume fraction and a dramatic rise in the onset of 3D superconductivity, from ∼10 to 32 K; however, the onset of at-least-2D superconductivity is much less sensitive to stress. These results show not only that largevolume-fraction spin-stripe order is anticorrelated with 3D superconducting coherence but also that these states are energetically very finely balanced. Moreover, the onset temperatures of 3D superconductivity and spin-stripe order are very similar in the large stress regime. These results strongly suggest a similar pairing mechanism for spin-stripe order and the spatially modulated 2D and uniform 3D superconducting orders, imposing an important constraint on theoretical models.

Topological Doping and Superconductivity in Cuprates: An Experimental Perspective

“…In the absence of strain, bulk susceptibility measurements suggest an onset of 2D superconducting correlations, along with spin-stripe order, near 40 K; however, the spin-stripe order is weaker than at x = 1/8 so that 3D superconducting order develops below ∼12 K [5]. Application of significant in-plane stress causes the bulk superconducting T c to rise to 32 K, while muon-spin-rotation spectra indicate a reduction in the magnetically ordered volume fraction by more than 50%, consistent with a decrease in the volume of spin-stripe order and associated PDW order [96]. While the dominant character of the superconducting state changes under strain, the onset temperature of superconducting coherence changes relatively little.…”

“…The close relationship between the PDW and uniform superconducting orders is illustrated by a study of the phase transitions in LBCO x = 0.115 as a function of uniaxial strain [96]. In the absence of strain, bulk susceptibility measurements suggest an onset of 2D superconducting correlations, along with spin-stripe order, near 40 K; however, the spin-stripe order is weaker than at x = 1/8 so that 3D superconducting order develops below ∼12 K [5].…”

Nature of the magnetic stripes in fully oxygenated La2CuO4+y

“…Additional support for the competition scenario is the observation of enhancement of the elastic IC response on application of an external magnetic field perpendicular to the CuO 2 planes, indicating that suppression of the superconducting order goes hand-in-hand with a strengthening of the magnetic order [17,[20][21][22][23][24][25][26]. The other way around, it was recently demonstrated that suppression of magnetic order by strain leads to a dramatic increase in T c in LBCO [27].…”

Observation of Cu Spin Fluctuations in High-Tc Cuprate Superconductor Nanoparticles Investigated by Muon Spin Relaxation

“…The 1/8 anomaly is a phenomenon where the T c is suppressed at x = 1/8. The suppression of T c at x = 1/8 was proposed due to the incommensurate magnetic ordering [20][21][22][23][24]. This was linked to the stripe theory in which the spin domain and hole domain are self-organized in the CuO 2 plane [20,22,24].…”

“…The suppression of T c at x = 1/8 was proposed due to the incommensurate magnetic ordering [20][21][22][23][24]. This was linked to the stripe theory in which the spin domain and hole domain are self-organized in the CuO 2 plane [20,22,24]. In the case of ferromagnetic spin fluctuation, it was predicted to occur in a highly over-doped regime at x > 0.25 causing the suppression of superconductivity in this regime [25,26].…”